Round balers generally have a bale forming chamber defined by a pair of opposing side walls associated with an array of side-by-side belts, transverse slats trained on chains, a plurality of transverse rolls or a combination of these various elements, e.g., rolls and belts. During field operation, windowed crop material such as hay is picked up from the ground and fed in a continuous stream into a fixed or variable diameter chamber. The hay is rolled into a cylindrical package within the chamber, wrapped with twine, net or the like and ejected onto the ground for subsequent handling.
U.S. Pat. No. 5,444,969, issued Aug. 29, 1995 in the name of Robert A. Wagstaff, et al, discloses a prior art round baler of the general nature described above. In this particular type of baler an expandable chamber is defined by a pair of fixed sidewalls, and a plurality of side-by-side belts cooperating with a series of transverse rolls, mounted between a pair of pivotally mounted arms. This arrangement of rolls and arms is commonly referred to as a sledge assembly. In the vicinity of the chamber where the belts and rolls operate in close proximity the transverse roll closest to the belts strips material from the adjacent belts that are trained about what is referred to as a follower roll. This is a common expedient in prior art balers having a chamber defined by rolls and belts.
The chamber includes an inlet opening in the front through which crop material is fed. Also included is a pair of take up arms pivotally mounted on the main frame, between which arms a pair of guide rolls are journalled. A biasing force on the take up arms urges the outer surfaces of the guide rolls against the belts to maintain tension and thereby prevent slack from occurring in the belts during expansion and contraction of the chamber. Density of the bale can be affected by varying the force on the take up arms.
The present invention relates to an improved round baler in which a cylindrical package of crop material is formed in a chamber comprising fixed side walls and expandable transverse elements consisting of a combination of belts and rolls of the general nature described in the preceding paragraph. The '969 patent, cited above, is an example of many prior art patents, assigned to New Holland North America, Inc., that disclose this type of round baler. It is not uncommon in prior art round balers having this general configuration for small amounts of crop material from the outer surface of the cylindrical package in the chamber to have a tenancy to be carried by the belts around the follower roll and through the space between the stripper roll and the belts that are trained about the follower roll. One function of the stripper roll is to combat these losses. The top peripheral surface of the stripper roll is moving toward the bale chamber and in a direction opposite to the direction of the belts on the follower roll. This serves to urge back into the chamber stray crop carried away from the chamber by the belts. This stripping function has met with a varying degree of success due to the need to maintain a predetermined distance between the belts and stripper roll to accommodate slugs of randomly accumulated debris between the belts and follower roll. Frequency and size of these slugs of material varies depending on type of crop being baled and general operating conditions, e.g., amount of humidity, temperature, etc. One type of crop material that has been particularly troublesome is plants with longs stems. Thus some losses occur as material passes through the space, regardless of the stripping function of the stripper roll. If the space between the stripper roll and belts is reduced to overcome this leakage problem, then the occurrence of occasional slugs leads to other problems, not the least of which is poor belt tracking, binding, and even eventual belt deterioration. Serious consequences are also encountered when crop debris leaks into the wrapping area and interferes with the starting and cutting functions of the wrapping apparatus.
Unique characteristics of the present invention, described below, contribute to a round baler with reduced losses that, among other things, has improved efficiency and enhanced performance and durability.